3 Introduction Currently 75 GNSS satellites in spaceExpect to have 90 GNSS satellites in space by 2015; 120 satellites by 202045+ GNSS satellites in view over Asia / Pacific simultaneously by 2020All GNSS satellites are capable of supporting metre-level and high-precision positioning at centimetre-levelFollowing presentation describes some of the challenges presented by new satellites and signalsTest results provided to illustrate the benefit of new satellites and signals with latest RTK hardware / firmware

5 GNSS SpectrumL5L2LEXL1G2G3G1E1E5E6B1B3B2RTX / OmniSTAR116411891214121712371257126013001525155115591565157115791585159015991614Frequency [MHz]GNSS antennas and receiver RF components expanded to capture usable signals from E5 to G1 spectrumGood compatibility between GPS, QZSS and SBAS signal structureLong term compatibility on L1C and E1 signals with frequency and codingGalileo-E6; BeiDou-B3; and QZSS-LEX bands are to be regulated (limited access), even though B3 can be tracked and used today for RTKGPS (US)Galileo (Europe)GLONASS (Russia)InmarSATQZSS (Japan)IRNSS (India)BeiDou (China)SBAS (US)

6 BeiDou System Three satellite systemsBeiDou-1 (active ranging system) no Trimble supportBeiDou-2 (current system) used to be called Compass – subject of this talkBeiDou-3 (proposal to move B1 to L1) first MEO satellites may launch in 2014Current constellation5 GEOs / 5 Inclined GEOs / 4 MEOs / More MEOs in 2014GEOs are harder to acquire & track due to high data rate (2ms versus 20ms pre detection interval)Multipath errors are constant for static users of GEOs

7 BeiDou System Signals B1, B2 – supported by Maxwell VI ASICWhat’s publicB1 Open Service is “fully” publicB2 is an Open Service – not in the current ICDB2 is the same signal as B1 so it is supportedB3 is officially a restricted signal – even though current codes appear to follow a defined polynomial

9 CMRx Data FormatAdditional satellite observations naturally increases the size of the GNSS correction streamGNSS corrections need to be transmitted to rover from a reference station or VRS networkMany radio solutions have limited bandwidthCMRx format provides a high level of data compression, with strong resistance to transmission errors

12 RTK Test CampaignA test campaign was run in several regions around the world where GPS, GLONASS, BeiDou, QZSS and Galileo satellites are currently visible, including China, Australia and New ZealandData collected on baselines from 2km – 22km in a variety of environments:Most in high multipath, trees, significantly masked environmentsSome in relatively benign environments15 different baselinesMost data collected in China22km line from Perth Australia6km line from Christchurch New Zealand

23 Galileo RTK Galileo satellites are currently unhealthyTrimble firmware is Galileo capable/ready.Modify firmware to force the satellites to report they are healthy and hence are used in the RTK solutionEvaluate the RTK performance2-hour period with 3 Galileo satellites.2 identical rovers on an 8.9km line – real time testCommon antennaLocated in Melbourne AustraliaRX1 = GPS+GLN+QZSS+BDS+GalileoRX2 = GPS+GLN+QZSS+BDS

26 SummaryCurrent BeiDou constellation nearly doubles the number of visible satellites over AsiaAdditional satellites improve accuracy of position estimatesTests show addition of BeiDou improved 95% position errors by:5-75% horizontal8-68% verticalAdditional satellites help to reduce the overall impact of measurement noise and multipath errors

27 SummarySimilar incremental improvements in position accuracy noted with Galileo satellites in RTK solutionAdditional satellites lead to increases in RTK correction bandwidthCMRx format designed for increased satellite countsCMRx roughly 55% smaller than RTCM v3.xExpect to see significant improvements in position availability and accuracy when BeiDou, QZSS, Galileo constellations fully populated